1. Field of the Invention
This invention relates to a drain plug structure for use in opening or closing a drain port of a bath tab.
2. Related Art
As the related art, drain plug structure for a bath tub, it is well known in the art to provide a system in which the supporting member having a plug lid pivotally supported therein, for example, is held in the drain port and an operating part arranged at a position spaced apart from the supporting member is connected to the supporting member through a release wire, for example, Gazette of Japanese Patent Laid-Open No. Hei 9-60073.
Further, in the case of such a drain plug structure as described above, as shown in FIG. 5, a packing 102 arranged at a rear surface 101 of a plug lid 100 is closely contacted with a packing close-contact surface 103 of a drain port C to hold a water-tight state, so that there occurs a possibility that the plug lid 100 may protrude substantially from the bottom surface 104 of the bath tub and become a hindrance material when a person takes a bath.
In view of the foregoing, although the packing close-contact surface 103 is lowered by a certain step from the upper surface of the drain port C and a height of the plug lid 100 is made low a little as shown in the figure, practically it is lowered by an amount corresponding to a height lower than a thickness of the packing 102 and its practical effectiveness is quite low because of a wall thickness of a drain fitting for constituting the drain port and holding the supporting member, and a holding of the drain port diameter and the like.
Further, when it is desired to generate a clearance between the rear surface 101 of the plug lid and the upper surface of the drain port C and assure an amount of collapse of the packing 102 required for holding a water-tightness at this clearance under a state in which the packing 102 is closely contacted with the packing close-contact surface 103 because of the highest priority of assuring of the water-tightness, this clearance may become a cause for oppositely increasing an amount of protrusion of the plug lid 100 and the plug lid 100 becomes a step without a fail.